from bootstrapvz.base import Task
from .. import phases
from ..exceptions import TaskError
import host
import logging
import os.path
log = logging.getLogger(__name__)


class AddRequiredCommands(Task):
    description = 'Adding commands required for bootstrapping Debian'
    phase = phases.preparation
    successors = [host.CheckExternalCommands]

    @classmethod
    def run(cls, info):
        info.host_dependencies['debootstrap'] = 'debootstrap'


def get_bootstrap_args(info):
    executable = ['debootstrap']
    arch = info.manifest.system.get('userspace_architecture', info.manifest.system.get('architecture'))
    options = ['--arch=' + arch]
    if 'variant' in info.manifest.bootstrapper:
        options.append('--variant=' + info.manifest.bootstrapper['variant'])
    if len(info.include_packages) > 0:
        options.append('--include=' + ','.join(info.include_packages))
    if len(info.exclude_packages) > 0:
        options.append('--exclude=' + ','.join(info.exclude_packages))
    mirror = info.manifest.bootstrapper.get('mirror', info.apt_mirror)
    arguments = [info.manifest.system['release'], info.root, mirror]
    return executable, options, arguments


def get_tarball_filename(info):
    from hashlib import sha1
    executable, options, arguments = get_bootstrap_args(info)
    # Filter info.root which points at /target/volume-id, we won't ever hit anything with that in there.
    hash_args = [arg for arg in arguments if arg != info.root]
    tarball_id = sha1(repr(frozenset(options + hash_args))).hexdigest()[0:8]
    tarball_filename = 'debootstrap-' + tarball_id + '.tar'
    return os.path.join(info.manifest.bootstrapper['workspace'], tarball_filename)


class MakeTarball(Task):
    description = 'Creating bootstrap tarball'
    phase = phases.os_installation

    @classmethod
    def run(cls, info):
        executable, options, arguments = get_bootstrap_args(info)
        tarball = get_tarball_filename(info)
        if os.path.isfile(tarball):
            log.debug('Found matching tarball, skipping creation')
        else:
            from ..tools import log_call
            status, out, err = log_call(executable + options + ['--make-tarball=' + tarball] + arguments)
            if status not in [0, 1]:  # variant=minbase exits with 0
                msg = 'debootstrap exited with status {status}, it should exit with status 0 or 1'.format(status=status)
                raise TaskError(msg)


class Bootstrap(Task):
    description = 'Installing Debian'
    phase = phases.os_installation
    predecessors = [MakeTarball]

    @classmethod
    def run(cls, info):
        executable, options, arguments = get_bootstrap_args(info)
        tarball = get_tarball_filename(info)
        if os.path.isfile(tarball):
            if not info.manifest.bootstrapper.get('tarball', False):
                # Only shows this message if it hasn't tried to create the tarball
                log.debug('Found matching tarball, skipping download')
            options.extend(['--unpack-tarball=' + tarball])

        if info.bootstrap_script is not None:
            # Optional bootstrapping script to modify the bootstrapping process
            arguments.append(info.bootstrap_script)

        try:
            from ..tools import log_check_call
            log_check_call(executable + options + arguments)
        except KeyboardInterrupt:
            # Sometimes ../root/sys and ../root/proc are still mounted when
            # quitting debootstrap prematurely. This break the cleanup process,
            # so we unmount manually (ignore the exit code, the dirs may not be mounted).
            from ..tools import log_call
            log_call(['umount', os.path.join(info.root, 'sys')])
            log_call(['umount', os.path.join(info.root, 'proc')])
            raise


class IncludePackagesInBootstrap(Task):
    description = 'Add packages in the bootstrap phase'
    phase = phases.preparation

    @classmethod
    def run(cls, info):
        info.include_packages.update(
            set(info.manifest.bootstrapper['include_packages'])
        )


class ExcludePackagesInBootstrap(Task):
    description = 'Remove packages from bootstrap phase'
    phase = phases.preparation

    @classmethod
    def run(cls, info):
        info.exclude_packages.update(
            set(info.manifest.bootstrapper['exclude_packages'])
        )